Search

A series of Nb—W—Ln heterometallic polyoxometalates {Ln12W12O36(H2O)24 (Nb6O19)12} (Ln: Y, La, Sm, Eu, Yb) is prepared by e.g. hydrothermal reaction of K7HNb6O19, Na2WO4, Cu(OAc)2, SmCl3, trimesic acid, and en in a carbonate buffer at pH 10.5 (autoclave, 160 °C, 72 h, 70% yield).

Unprecedented radical cascade reaction of alkynoates with various ethers (II), amides (VI), benzylic compounds (Xa,b), cycloalkanes (Xc-e), and silane (Xf) is reported.

1,3-Dipolar cycloaddition of in situ thermally generated azomethine ylides with alkenyl substituted isoxazoles offers a convenient synthesis of fused spiropyrrolidine oxindoles in good diastereoselectivity.

The Y(OTf) 3 -catalyzed aerobic oxidative cyclization reaction for the selective synthesis of dihydroquinazolinones and quinazolinones has been developed. This method provides a practical, effective and green synthetic approach to dihydroquinazolinones and quinazolinones which both are important units in many biologically active compounds.

A variety of products bearing a hexahydro-1H-pyrido[2,3-b]indol-2-one core, a key structural skeleton in a large number of biologically active natural products and pharmaceutical compounds, are obtained with high efficiency.

A facile and efficient methodology is developed for the synthesis of multifunctional polycyclic spiropyrrolidine oxindoles via a three-component 1,3-dipolar cycloaddition reaction of dienones (III) with azomethine ylides (thermally generated in situ from isatin derivatives and proline or thioproline).

Most of the products show in vitro inhibition activity against Staphylococcus aureus (MTCC96) comparable to Penicillin.

Pd-catalyzed coupling of Morita—Baylis—Hillman carbonates with (triisopropylsilyl)acetylene (II) produces 1,4-enynes in good yields.

The YCl 3 -catalyzed aerobic oxidative cyclization reaction for the synthesis of benzothiazoles has been developed. This method provides a practical, effective and green synthetic approach to benzothiazoles which are important units in many biologically active compounds.

Optimized conditions allow the diastereoselective reaction of 3-aminooxindoles with α,α-dicyanoolefins to give the title compounds in high yields.

Prismatic crystals of [Ni(dap)2]3[WO4]3 [Ni6(dap)3 (OH)3PW9O34] 2·9H2O (dap: 1,2-diaminopropane) are prepared by hydrothermal reaction of an aqueous solution of Ni(O-Ac)2 and Na9[A-α-PW9O34] in the molar ratio of 1:0.13 to which dap is added dropwise under stirring (2 h) (autoclave, 170 °C, 3 d).

The first Lewis base-catalysed allylic sulfuration of Morita–Baylis–Hillman (MBH) adducts derived from ketones (isatins) has been developed, which affords C3-quaternary oxindole derivatives bearing thio-group at 3-position in good to excellent yield (up to 98% yield) under mild reaction conditions. Significantly, the potential utility of the protocol also has been demonstrated by gram-scale synthesis of 3-alkylthio-2-oxindole (3ae), a low catalyst loading (0.3 mol %) and facile conversion of resulting product (3ad) into functionalized pyrrolidinone (5ad).

The new compounds (III), (IV), and (V) are hydrothermally synthesized and characterized by powder and single crystal XRD, IR spectroscopy, and diffuse reflectance spectroscopy.

In this study, Yb immobilized NaY zeolite catalyst (Yb/NaY) was obtained by a hydrothermal method and characterized by XRD, BET, FT-IR, ICP-AES, and NH 3 -TPD. The catalyst displayed good catalytic activity when applied to the synthesis of quinoxalines via condensation of α-hydroxyketones with 1,2-diamines, and could be reused several times without any loss of catalytic activity.

A mild and efficient method for the construction of pyrrolidinyl spirooxindoles via a 1,3-dipolar cycloaddition reaction of (E)-N-Boc-3-alkylidene-indolin-2(3H)ones with azomethine ylides has been established. The presence of an N-Boc group in the indolin-2(3H)ones obviously increased the activity and stereoselectivity of the reaction, affording the desired pyrrolidinyl spirooxindoles 4 with up to 85% yield and up to >99/1 dr value. Furthermore, the antibacterial activity of these compounds against Staphylococcus aureus (ATCC-25825) has been tested at minimum concentration, and some of them exhibit moderate antibacterial activity. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]

A direct dehydrative coupling of terminal alkynes with allylic alcohols catalyzed by Pd(PPh3)4 with an N,P-ligand assisted by Ti(OiPr)4 has been developed. The coupling reaction tolerates various functional groups, providing a valuable synthetic tool to access 1,4-enynes.

The title nanorods are prepared by reaction of zinc acrylate dispersed in toluene with an aqueous solution of NaHTe in the presence of oleic acid as capping ligand at the toluene/water interface (90 °C, 4 h).

A series of novel Ln-substituted polyoxometaloaluminates, K2(H2O)4Ln(H2O)7 [Ln(H2O)3HAlW11O39]· nH2O (Ln: Nd, Eu, Gd, Tb, n = 7; Ln: Pr, n = 8; and Ln: Sm, n = 9) are hydrothermally prepared from K9[AlW11O39], Ln(NO3)3, and H2O together with MnCl2 and 2-picolinic acid acting as buffer and complexant, resp.

Structurally diverse 3,3′-thiopyrrolidonyl spirooxindoles bearing three contiguous stereogenic centers can be smoothly prepared via domino Michael/cyclization reaction using quinine as chiral catalyst.

α-Arylsubstituted cyanoacetates react with various N-substituted maleimides to afford products bearing 2 vicinal quaternary-tertiary stereocenters.

It allows a straightforward and highly stereoselective access to the title compounds which are of biological interest.

An efficient Michael addition of indoles to electron-deficient olefins under solvent- and catalyst-free condition afforded biologically important 3-substituted indole derivatives in good to excellent yields was reported. The acidic NH proton of indole plays a key role in Michael addition of indoles to electron-deficient olefins. This very simple procedure provides an efficient and clean process for the synthesis of indole derivatives. J. Heterocyclic Chem., (2011).

For some examples, the corresponding hydroxymethylation product is observed as the major component.

It allows a mild, efficient, and highly enantioselective access to a number of 3,3-disubstituted oxindoles.

The reaction tolerates a variety of substituents at the C3- and C5-positions of the indoles and various N-substituents in maleimides (II).

The research progress in trialkyl compounds of gallium and indium was discussed from two aspects, one was the chemical synthesis of the compounds and the other was the purification of them. There are three synthesis routes being reported in the first aspect, i.e. the route staring from pure metal, the route starting from the pure metal trihalides, and the electrochemical route. In the second aspect, the purifying methods of decomposition-distillation and zone refining were reviewed.

Five new prenylated flavonoids, maackiaflavanone A (1), maackiaflavanone B (2), maackiapentone (3), maackiapterocarpan A (4), maackiapterocarpan B (5) along with eleven known flavonoids were isolated from the stem bark of Maackia amurensis. The structures of the new compounds were elucidated by spectroscopic methods. The cytotoxicities of compounds 1-4, 6, 8-12 and 14-16 against four human cancer cell lines, A375S2, HeLa, MCF-7 and HepG2, were tested by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Among the compounds tested, compound 2 showed the strongest cytotoxic activity with IC(50) value of 7.8 microM against A375S2 and euchrenone b(1) showed the most potent cytotoxicity with IC(50) value of 4.5 microM against HeLa.

Under selected conditions, 1,2:3,4-doubly crowned p-tert-butyl-thiacalix[4]arene in cone conformation and 1,3:2, 4-doubly crowned p-tert-butyl-thiacalix[4]arene in 1,3-alternate conformation were obtained through aminolysis in high to good yield, respectively.